Tools/terrain_from_dem.py builds a 191x106 grid at 2 m over the block, Z being
NAVD88 minus the origin ground. Building footprints from the OSM extract are cut
out so rooftops never become terrain (72 footprints, 6310 cells). Spot checks
reproduce the measured profile: origin 0.00, Orange Dr +3.39, south gutter
+0.93, crown +1.38, north sidewalk +1.43.
Blosm projects with a sphere, not an ellipsoid, so its frame was ~0.4% oversized
and rotated by meridian convergence: about 2 m at the theatre. The blockout now
fits a six-parameter affine into EPSG:26911 on five control points (0.0 cm
residual) and transforms root objects only, since children inherit and double
transforming them read as a 2 m placement error.
The OSM north edge measures 25.74 m, the sibling notes' own column spacing
(5 bays x 4.96 m + one column) gives 25.70 m, and the photo framing agrees.
The 29.6 m figure has no derivation and is dropped rather than averaged. The
neighbour outlines overlap by 0.1-0.3 m, so they are traced shared walls, not
approximate bubbles.
Gutters sit at -10 m south and +10..12 m north, a ~2% crown between them, and
the envelope runs 0.6-1.0 m per section. Gutter spacing independently confirms
the 20.9 m carriageway measured from the crossing. The sharpest breaks are
0.09-0.12 m/m, so 3DEP does not resolve a kerb upstand: kerb height stays a
recorded assumption rather than a derived value.
550x350 m clipped to the block, already in the project CRS, 984 KB, committed
through LFS. Verified against the service's own point query and the earlier
probe: 115.911/119.422/117.593 m, agreement within 6 cm.
Adds Geo/scripts/dem_stats.py, a stdlib tiled-TIFF reader, because GDAL cannot
run on the host and the exported raster is tiled rather than strip-organised.
Probe 22 points with the USGS 3DEP point service: walkable surfaces span
115.65-119.59 m, a 3.94 m relief, so elevation data is required by the AGENTS
rule. Grade falls ~3.3 m eastward over the 279 m block (1.2%) and the north
sidewalk sits 0.4-0.7 m above the south. 3DEP 1 m is public domain and becomes
the chosen source; the tile itself is still to be downloaded.
Factored the shared OSM helpers into Geo/scripts/osm_common.py so the street
profile and the elevation probe read the same geometry.
New Geo/scripts/street_profile.py measures the 279.4 m block centreline, the
three signalised crossings (20.9-25.9 m across), sidewalk centrelines at 12.6 m
and 13.6 m, and per-building setbacks of 13.0-15.8 m. Derived sidewalk widths
of ~4.0 m south and ~5.3 m north cross-check against the mapped centrelines.
Geo/manifests/local-origin.md fixes EPSG:26911 and the Highland intersection
node as origin, defines the axes and the x100 metre-to-centimetre rule, and
leaves the projected pair blank because PROJ is not installed here.
Records the lane-count discrepancy (4 tagged lanes over a 20.9 m carriageway).
Inventory the sibling security-game project and copy only the evidence: nine
licensed photos with their sidecar provenance into Art/reference/hollywood/,
now LFS-tracked. Add the block-wide OSM extract with a manifest, resolve the
demo bounds (Orange Dr -118.341434 .. Highland Ave -118.338718, 279 m) and the
south/north building sets, and add Geo/scripts/block_report.py to reproduce it.
The sibling docs place the El Capitan Theatre west of 6840; OSM geometry and
the house numbering put it east. Recorded with the two unresolved measurement
conflicts rather than averaged.
Nominatim plus the OSM API confirm 6840 Hollywood Blvd as way 424024147
(Hollywood Masonic Temple, Q3139424), footprint ~1387 m2. The neighbouring
El Capitan Theatre is a separate way with a different amenity and size, so the
two stay distinct structures. Raw responses are checksummed in Geo/raw/.
zwitschi